def intersection(list1, list2):
    result = list(set(list1) & set(list2))
    result.sort()
    return ','.join([str(x) for x in result])

assert intersection([1, 3, 2], [4, 3, 2]) == '2,3'
assert intersection([1, 2, 6, 4, 5, 7], [10, 2, 3, 4, 8]) == '2,4'
assert intersection([1, 3, 5], [2, 4, 6]) == ''